1. Field of the Invention.
This invention relates generally to the field of building construction and more specifically to articles of manufacture for transporting daylight through building plenum.
2. Description of the Prior Art
Originally, daylighting with skylights could be found in building such as warehouses, for example, without ceilings between roof and floor. This form of daylighting had low requirements, with less need for tight design specifications as is now required by architects when designing complete building envelopes, with daylight as a primary factor. See analysis software called SkyCalc, at the following web site info@h-m-g.com, <mailto:info@h-m-g.com>. This software provides for analysis of electricity and money saved when daylighting buildings. California, in an effort to promote daylighting in commercial buildings, has awarded a skylight manufacturer Sola tube with incentives for installation of their products.
Previous studies have shown that skylighting, or toplighting with daylight, has dramatic potential for saving lighting energy (with cooling energy savings as a byproduct). These studies have shown examples of good (and sometimes bad) toplighting, but they have nearly all been one-of-a-kind designs.
In general, most practitioners are quite reluctant to take on the risk of developing one-of-a-kind designs for a ceiling system that must integrate several components from different manufacturers (skylight, ceiling and light well, electric lighting, photocell controllers, air diffusers, etc.). Applicant knows of no work that has proposed prototype designs, except in the most general sense, for integrated ceilings that could be standardized and repeatable. Preliminary discussions with Armstrong Ceilings, the largest manufacturer of ceiling systems in the country, indicates that neither they nor any other manufacturer of ceiling systems is likely to undertake this kind of integrated design development. They would, however, be willing to participate in the development of industry standards for integrating different manufacturers' products, provided there was leadership and impetus for such an effort. These standards would entail development of design standards and specifications for interconnection details between components (e.g. skylight-to-light-well connections, or photocell to controller-to-dimming-ballast connections).
About 60% of nonresidential floor space in California is directly under a roof, and 90% of new floor space is single story construction. There is, therefore, a huge potential floor area suitable for toplighting applications. Skylighting is not widely applied by building designers or owners because each skylighting design requires the careful integration of ceiling system, skylight, light shaft, electric lighting, photo control, and, often, air distribution systems. This problem has been discussed for over fifteen years within the building science community, yet the resources (federal or industry funding) has never materialized for this work to take place.
In both amounts of foot-candle requirements and control sophistication the daylighting of ceilings in buildings, including ceilings suspended from roof structures were not recognized as opportunities for daylighting, and existed outside the realm of affordable, or practicable daylighting, for numerous reasons. Some of these reasons are, existing physical obstructions restricting straight paths, for daylighting shafts, in vertical directions, and small semi-flexible shafts typical of tube type products lack the volume necessary to honestly turn off the building lights. In addition, the following factors have imbedded the adoption of daylighting by the mechanical or trades, integration of electric fixtures and other types of pipes, wires, ducting, general interior finish of suspended ceiling products, such as surface finish, non-interruptible wire connections from roofs to suspended ceilings, elements of the grid framework systems' resistance to impact by weight, movement, or deformity, process in which suspended ceiling installation requires complete assemblage, to provide dimensional integrity, effectively restricting installation labor, for light shaft installations, and resistance to removal and replacement of grid members.
The foundation, for the layout of the light fixtures, commonly referred to in the building trades as a reflected ceiling plan, is a design criteria driven by the requirements of electric lights, and their distribution throughout the utilized space. As a result, daylighting integration for suspended ceilings needs to be considered at the design stage of construction.
With current demands for energy efficiency and improved occupant living and working environments, as evidenced by published daylighting programs such as SkyCalc, and extensive daylighting studies indicating improvements in student scores, in day lit classrooms, there is a real need for the integration of daylighting processes and suspended ceiling applications.
Throughout the years, a number of innovations have been developed relating to skylight construction, and the following U.S. Pat. Nos. are representative of some of those innovations: U.S. Pat. Nos. 4,610,116; 4,788,804; 4,823,525; 5,044,133; and Des. 328,795. More specifically, U.S. Pat. Nos. 4,610,116, 4,788,804, 4,823,525, and 5,044,133 relate to roof-mounted skylights.
A skylight using a reflective fabric shaft has been described in U.S. Pat. No. 4,733,505. Skylight construction of various configurations has been discussed in the following U.S. Pat. Nos. 219,840; 3,012,375; 3,052,794; 3,064,851; 3,113,728; 3,130,922; 4,114,186; 4,161,918; 4,339,900; 4,365,449. The subject is also discussed in literature, Rodale's New Shelter, November/December 1983, Smart Skylights by Kathy Kukula, pp. 48-50, a brochure by Freeman Skyflex, 4 pgs., and a brochure by Kenergy Corp., 2 pgs.